Micrometer attachment



Dec. 21, 1948.

C; L. KEMP MICROMETER ATTAQHMENT Filed April 26, 1946 ll/II INVENTOR ATTORNEYS Patented Dec. 21, 1948 UNITED STATES PATENT Charles L. Kemp, Klamath Falls, Oreg. Application April 26, 1946, Serial No. 665,248

2 Claims. 1

This invention relates to'an attachment for micrometers whereby a micrometer can be converted to an outside micrometer designed primarily for taking minute measurements of crank shafts and other objects located at points dimcult of access.

It is a further object of the invention to provide an attachment which is simple, strong and efficient, it being possible to join a micrometer to the attachment whereby, through cooperation of the parts, the desired outside measurements can be obtained.

With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts hereinafter more fully described and pointed out in the claims, it being understood that changes may be made in the construction and arrangement of parts without departing from the spirit of the invention as claimed.

In the accompanying drawing the preferred form of the invention has been shown.

In said drawing:

Figure 1 is a front elevation of the attachment assembled with a portion of a micrometer, parts being broken away.

Figure 2 is a section on line 22, Figure 1.

Figure 3 is an enlarged view partly in section and partly in elevation showing the means for effecting a quick adjustment of the micrometer insert.

Referring to the figures by characters of reference I designates an elongated jaw which can be tapered off to a reduced end 2 the inner side of which can be finished to form a contact face 3 for use in making outside measurements. Extending from that end of the jaw remote from the point 2 is a guide rod 4 on which is slidably mounted a jaw 5 having a reduced extension 6 terminating in an end I the other side of which is also finished off to provide a contact surface 8. This surface 8 cooperates with the surface 3 for the purpose of making outside measurements.

The inner side of the main or thickened portion of the jaw 5 is formed with an elongated recess 9 one end of which terminates close to the meeting point of said main portion and the reduced extension 6 of the jaw, the other end terminating close to the guide rod 4 (see Figure 2). Opening into the recess intermediate the ends thereof is a circular socket ID. This socket is proportioned to receive one end of the thimble A of a micrometer, said thimble being provided with an annular groove B in which are seated the recessed ends ll of opposed retaining plates I2 detachably secured by means of screws [3 within the elongated recess 9. A

The thimble A is mounted on the usual sleeve C from which a spindle D extends but in the present case the free end of the spindle is screw threaded as shown at E so as to be inserted into tight engagement with the jaw I, the end of the spindle adjacent to the screw threads E being provided with a kerf F by means of which the spindle D can be rotated to feed it into or out of the jaw l for the purpose of getting the proper adjustment and assembly. At regular intervals recesses G are provided in the spindle and any one of these recesses is adapted to receive a pointed pin H guided within a sleeve I mounted on sleeve 0. A tubular cap J surrounds sleeve I and has the pin H extended from it. Obviously by rotating cap J the pin H can be adjusted longitudinally so as to move into or out of one of the recesses G, thereby holding the spindle D securel against longitudinal movement relative to the micrometer sleeve C.

When it is desired to attach the present invention to a micrometer, the frame and anvil usually forming parts of the micrometer, are removed, thereby leaving only the thimble A, sleeve C and spindle D. The micrometer can be equipped already with the groove B, the sleeve I and the parts associated therewith, and the threaded portion E and recesses G.

After the anvil and the frame have been removed, the thimble A is inserted into the socket I0 and the plates l2 are secured in place with their recessed ends ll seated in the groove B. Thus the thimble A is held assembled with the jaw 5. The threaded end of the spindle D is then placed in engagement with the jaw l and the parts are accurately adjusted relative to each other so that the measurements on the micrometer will be usable in connection with the working faces 3 and 8 of the jaws I and 5. Quick adjustment of the jaws relative to each other can be effected by disengaging pin H from one of the recesses G and shifting it into position within another recess G. As these recesses are spaced apart predetermined distances, such adjustment will not affect the readings made with the attachment.

After all parts have been correctly adjusted, the micrometer thimble can be rotated as usual for the purpose of feeding the sleeve and spindle in one direction or another, thereby setting up a corresponding movement of the jaw 5 relative to the jaw I so that the reading on sleeve C, in

. 3 connection with the predetermined distance effected by the positioning of the pin H, can be utilized for the purpose of getting an accurate measurement between the wooden faces 3 and 8.

Because of the design and arrangement of the parts, it has been found that when a micrometer is combined with an attachment as herein described, very accurate measurements of parts located at points difficult of access, can be made readily; The attachment hasybeen found especially useful when it is .desired to-make measurements of crank shafts and other parts of the mechanism of an automobile, engines and power plants, etc. 7

What is claimed is:

4 contact with the outer surface of an object to be measured.

2. The combination with the thimble, sleeve and spindle of a micrometer, and means for holding the spindle adjustably to the sleeve, of 0pposed jaws, a guide rod extending from one of the 'jaws, the other jaw being slidably mounted on the rod and having a socket, the thimble of the micrometer being seated and rotatable within the socketmeansc-detachably secured to: the slidable jaw and cooperating with the thimble for retaining said thimble in the socket, an adjustable, de-

tachable connection between the spindle and the 1. The combination with the-.thimble;sleeve and spindle of a micrometer, and means for effecting quick adjustment between the spindle and the sleeve, of opposed jaws, a guide rod fixedly connected to onewof the jaws and slidably engaged by the other jaw, a socket in the slidable jaw,:'said socket 'providingja'seat for the thimble of the micrometer, means mounted on the movable jawfor holding .the ,thimble to theseat, a detachable and adjustable connection between the spindle and the other jaw, and extensions on the opposed jaws havinginside working, faces for otherjaw, and extensions on the jaws projecting -awayfrom-the rod, said extensions having inner working facesconstituting means for engaging the outer surface of an object to be measured.

' CHARLES L. KEMP.

REFERENCES CITED 1,070,816 Kunik- ,Aug. 19-, 1913 

